IPv4 Subnet Mask Cheat Sheet

December 13th, 2017
115 words · 1 minutes read · 0 Comments

A quick overview “cheat sheet” of IPv4 Subnet masks.. This comes in surprisingly handy more often than I first imagined it would.

Addresses Hosts Netmask Amount of a Class Class
/30 4 2 255.255.255.252 1/64 C
/29 8 6 255.255.255.248 1/32 C
/28 16 14 255.255.255.240 1/16 C
/27 32 30 255.255.255.224 1/8 C
/26 64 62 255.255.255.192 1/4 C
/25 128 126 255.255.255.128 1/2 C
/24 256 254 255.255.255.0 1 C
/23 512 510 255.255.254.0 2 C
/22 1024 1022 255.255.252.0 4 C
/21 2048 2046 255.255.248.0 8 C
/20 4096 4094 255.255.240.0 16 C
/19 8192 8190 255.255.224.0 32 C
/18 16384 16382 255.255.192.0 64 C
/17 32768 32766 255.255.128.0 128 C
/16 65536 65534 255.255.0.0 1 B
/8 16 M 16 M -2 255.0.0.0 1 A
/1 2048 M 2048 M -2 128.0.0.0 128 A

For more information on this topic please see RFC 1878


Posted in: Tech
Tagged: linux, networking

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